PROM1 and neoplasm: For CD133, we observed positive crypts in 9-month-old Apc background mice with spontaneous colorectal tumors, compared with control 4-month-old Apc mice without any tumor visible by colonoscopy (Fig. 3e, f, Supplementary Fig. 9e, f, Supplementary Fig. 10a–c, and Supplementary Note 9).